1. Field of the Invention
The present invention relates to an ink jet recording apparatus, particularly to a nozzle recovery method for the ink jet recording apparatus.
2. Description of the Related Art
Suction recovery processing is performed on an ink jet recording apparatus when clogging of ink occurs on discharge nozzles of a recording head, or when there is a risk of defective printing caused by bubbles entering an ink flow path. Performing the suction recovery processing enables discharge-interrupting objects such as foreign objects, thickened ink, and bubbles to be discharged to the exterior through the nozzles. However, when ink is suctioned by the conventional suction recovery processing, flow velocity of the ink is lower in an end portion than in a central portion of a common liquid chamber, which communicates with the nozzles. Therefore, it is problematic in that the bubbles accumulated in the end portion of the common liquid chamber cannot be discharged easily.
Japanese Patent Application Laid-Open No. 2003-291374 discusses a technique in which a structure that reduces a flow path sectional area is provided within a cap, and flow velocity in specific nozzles is selectively increased by moving the structure along a nozzle row. Japanese Patent Application Laid-Open No. 11-320877 discusses a technique in which flow velocity in the end portion of the common liquid chamber is increased by making flow path resistance of the central portion of the common liquid chamber be greater than that of the end portion thereof. Japanese Patent Application Laid-Open No. 11-334108 discusses a technique in which flow velocity in the end portion of the common liquid chamber is increased by suctioning the ink while the nozzles at the central portion of the nozzle row are blocked by the structure of the cap.
However, in any of the above-described conventional techniques, the structure may be newly added to the recording head or the cap, or the structure of the recording head or the cap may be changed. Therefore, there is a problem in that the structure thereof becomes complicated. This may result in increase in cost, increase in frequency of failure to occur, and increase in size of the apparatus. Further, in the configuration according to Japanese Patent Application Laid-Open No. 11-320877, changing the shape of the common liquid chamber may have a negative effect on the original ink discharging performance. In the configuration according to Japanese Patent Application Laid-Open No. 11-334108 where the cap contacts the discharge ports, foreign objects may easily enter the nozzles, and thus, there is a risk of increasing the frequency of ink discharge failure.